Fixing Perl5 Core Bugs: Report for Month 37

This month I mainly worked on one of the 5.18 blocker tickets; in this case how

overload::constant qr => sub { ...}

interacts with "constant" regexes such as qr/foo/ and qr/foo(?{bar})/ if the sub replaces constant strings like "foo" with an overloaded object. It turns out this was something I hadn't anticipated in my re_eval reworking, and my code didn't handle it at all well. I'm now about 3/4 the way to fixing it.